Owing to advancement of wireless communication technologies, a wide variety of wireless signal transmission devices such as mobile phones, personal digital assistants (PDAs), notebook computers and the like have found wide application in people's daily life. Correspondingly, network services that can be realized through the wireless signal transmission devices also become increasingly diversified. For example, people now can download music pieces and enjoy online movies both in a real-time manner via the wireless signal transmission devices. These network services not only provide people with more convenient network applications, but also dramatically increase the added value of the wireless signal transmission devices.
From the perspective of a base station (BS), all the wireless signal transmission devices described above may be viewed as subordinate stations (SSs). In order to improve the power utilization efficiency of an SS, the SS will enter a power-saving state when no network service is needed, so as to effectively extend the battery life. Furthermore, when an emergency condition occurs, the BS will transmit emergency information to the SS to notify the user of the SS. However, in case the SS is in the power-saving state, it will fail to receive the emergency information, so the BS must retransmit the emergency information to the SS when the SS resumes the active state, thus leading to unnecessary waste of network resources.
Accordingly, an need exists in the art to provide a solution that enables an SS that is in a power-saving state to successfully receive emergency information from a BS and to perform corresponding actions according to the emergency information, so as to improve the utilization efficiency of network resources.